The long-term goal of our studies is to understand how nervous systems are assembled during development. To approach this general question we have used two different insect species, the house cricket Acheta domesticus and the fruitfly Drosophila melanogasta, a variety of technical approaches, and three general experimental designs: (a) description of normal development, (b) perturbation of normal development by surgery, and (c) perturbation of normal development by suitable mutations. Neither the insects we use nor the methods are hazardous. Our chemicals are stored and disposed of according to University regulations; sharp objects such as broken glass are kept in marked containers and disposed of through University channels.